The present disclosure generally relates to enhancing images from electronic displays, and specifically to reducing light leakage within an optical system of electronic displays.
In a head-mounted display (HMD) a user's eye occupies a region of space generally referred to as an eye box (typically there is a respective eye box for a left and a right eye of the user). The HMD displays and directs content to the eye boxes. In some conventional systems multiple optical elements direct the content to the eye boxes, and light can be reflected in between optical elements and parasitic reflections can lead to poor contrast in the content being presented to the user. In particular, systems with multiple polarizing elements, which if not handled correctly can result in parasitic light and/or ghost images that can dramatically reduce overall image quality.
Additionally, as a user moves their eye within an eye box and/or the position of the HMD changes relative to the position of the user's head, the location of the user's eye within an eye box may change. Changes in the location of the eye within an eye box may result in distortions in the content being presented to the user. This effect is known as pupil swim, and it can be a problem for HMDs for various reasons including, e.g., increased calibration difficulty, and motion sickness due to problems with vertical disparity. Conventional approaches for reducing pupil swim add complexity to HMDs.